秦岭老君山森林土壤微生物量碳氮的分布

Distribution of Microbial Biomass Carbon and Nitrogen in Forest Soil of Laojun Mountain in Qinling Mountains

摘要: 土壤微生物量是陆地生态系统碳循环的重要组成部分，在森林生态系统物质循环和能量转化中占有非常重要的地位。本研究以秦岭余脉八百里伏牛山的主峰老君山为研究对象，探讨了森林土壤中微生物量碳、氮含量随着海拔与土壤深度变化的分布状况。结果表明，海拔1300 m、1600 m、1900 m土壤微生物量碳含量分别是501.68 mg/kg、861.75 mg/kg、980.93 mg/kg；其土壤微生物量氮含量分别是5.50 mg/kg、5.94 mg/kg、7.07 mg/kg。土壤微生物碳随土层深度的变化，则是在每个海拔的规律则是一致的，都随土壤层的加深而增加。在海拔1300 m和1900 m时，30~45 cm土层土壤微生物量氮含量显著高于其它3土层；而在海拔1600 m时，则是45~60 cm土层最高，且显著高于其它土层。总体而言，土壤微生物量碳、氮含量随着海拔的增高而增加；下层土壤(30~60 cm)微生物碳、氮含量高于上层土壤(0~30 cm)。 Soil microbial biomass, as an important portion of terrestrial ecological carbon budget, plays a key role in material cycles and energy transformation in forest ecosystems. The distribution of soil microbial biomass carbon (SMBC) and nitrogen (SMBN) along the variations of elevation and soil depth was studied in forest soils of Laojun Mountain, the highest peak of Funiu Mountain in Qin Mountains. The concentrations of SMBC were 501.68, 861.75 and 980.93 mg/kg at elevations of 1300m,1600m, and1900m, respectively. The concentrations of SMBN were 5.50, 5.94 and 7.07 mg/kg at elevations1300m,1600m, and1900m, respectively. The SMBC increased with soil depth regardless of elevations: the SMBC concentration was the highest at 30 -45 cmdepth at elevations of 1300 and1900m. The highest SMBC concentration was present at 45 -60 cmdepth at the elevation of1900 m. The tendency of SMBN was accordant at three sites of different elevations, which increased with soil depth. In summary, the SMBC and SMBN increased with the elevation, and the SMBC and SMBN were higher at the depth of 30 -60 cmthan the 0 -30 cmdepth.